


Necronomicum

by a_very_large_television



Category: Persona 5, Persona Series
Genre: Anal Sex, Ass Play, Belly Kink, Chubby, Clothed Sex, Come Inflation, Consentacles, Enemas, F/F, Large Ass, Other, Tentacle Sex, Tentacles, Tight Spaces, Weight Gain, a lotta cum inflation, all the way through, at the very end, does it count as an enema if its a tentacle, i guess its an enema, just cum gushing out not any tentacles, makoto has a fat ass, stuck, stuckage, the scene itself is mostly cum inflation, theres nothing gross or anything just a butt getting filled with cum, very mildly dubious consent for like a second, well the weight gain is more of a background thing
Language: English
Status: Completed
Published: 2020-02-20
Updated: 2020-02-20
Packaged: 2021-02-28 05:53:30
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 3,937
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22808926
Author URL: https://archiveofourown.org/users/a_very_large_television/pseuds/a_very_large_television
Summary: [Edited RP log] Makoto gets her butt stuffed with Necronomicon's tentacles and gets pumped full of cum and loves it. Futaba helps.This one's a little bit weird.
Relationships: Niijima Makoto/Necronomicon, Niijima Makoto/Necronomicon (Persona 5), Niijima Makoto/Sakura Futaba
Comments: 12
Kudos: 63





	Necronomicum

**Author's Note:**

> this is another RP thing i did with a friend! with her permission, i took the logs and did some editing so it all flows together and is easier to read in a narrative format.
> 
> my friend doesn't have an account on Ao3, but she can be found under the username Hackerchan on F-List! she's an excellent writer, and this was an absolute thrill to write out with her.
> 
> also happy birthday futaba.

They were both pulled into the macabre, staunch red and black of Mementos, and Makoto's head idly turned to glance at the entrance of the subway station laid bare. It was strange to be there alone with Futaba and none of the others backing her up, though it would  _ probably _ be fine. It wasn't like they had vanished off to get into a scrape with Shadows.

A little idle tug on her iron mask, and a little glance down her body - at the exceptionally-tight suit clinging to her curves, and the leather girdle tied across her midsection. Yep, definitely in the Metaverse again.

Makoto had an  _ idea _ of why they were here, and the thought made her blush across the cheeks a little as she glanced over her shoulder and then swung around on a heel to face Futaba. Futaba, who, despite looking so worryingly-scrawny in the real world, was packing enough of a gut to stretch the front of her suit in the Metaverse as of late.

A beat, and Makoto finally spoke up as her eyes scanned over her friend’s bulging tummy again. "So! Um. H-How did you want to go about this?" The usual veneer of confident authority was  _ already _ faltering.

Hands behind her back as Makoto’s eyes met hers, Futaba couldn’t help but laugh. Makoto was a sweetheart, a wonderful advisor to the rest of the team, and utterly terrifying in her brawls against Shadows in the depths of the Metaverse. That didn’t stop her from turning into a nervous, stammering wreck whenever she was embarrassed, and good god, how easily Makoto Niijima got embarrassed. Futaba thought it was so cute! One of those hands swung around and took a big, fat pinch of Makoto's bottom - a bottom already wide enough to not quite need what it was about to receive.

There had been some unsubtle pondering amongst the Phantom Thieves lately on why Futaba looked so much plumper in the Metaverse. Futaba'd managed to pass off some lie about unhealthy eating and drinking habits as well as a poor lifestyle that hung heavy in her mind, twisting things in the cognitive world - but one person had followed up on trying to help Futaba be healthier, promising to coach, encourage. Enough prying, and Futaba finally spilled the beans. She definitely hadn’t expected Makoto to ask what she asked next.

The surprise little squeeze to her rather… prodigious ass was enough to make Makoto suddenly jolt, body straightening, eyes widening. The sheer tightness of her biker suit left it to blatantly ride up those ample cheeks, leaving little to the imagination - and bunching up and spilling quite a bit of fat, thick skin over Futaba's fingers. Even constrained by that bodysuit - poorly, mind you, those cheeks  _ fat _ enough that Makoto looked like she was just one wrong step from a major wardrobe malfunction - there was just so much!

Her body jerked away, just a smidge, and she looked down to Futaba with a half-pout in her face and cheeks redder than her eyes. Futaba - noticeably missing those big, ridiculous goggles that served as her Persona-summoning mask - just wore a shit-eating grin as her gaze turned from Makoto to glancing across the cold floor of the subway platform.

"Let's see... ooh, there works. See that hole?" Futaba gestured to a perfectly-circular little sinkhole in the floor, from which ominous little green lights spilled out. Makoto’s keen eye spotted the familiar looking insides and motifs of the Necronomicon, sunken into the floor. "Just slip down there and I'll take care of the rest! As long as you want to end up looking like me, heh-heh-heh...."

Beat. "A-Alright," Makoto said with no small amount of nervousness. Eager? Absolutely. Eager enough she had worked up the courage to ask Futaba to help her indulge in such a bizarre, embarrassing kink. Eager enough she had blown off an after school student council meeting she  _ definitely should not be missing oh my god she’s gonna get in so much trouble but who cares _ . Eager enough she was doing it  _ right now _ , step after step to make her way to that terrifying little hole filled with… tentacles, she saw as she got closer. Necronomicon-looking tentacles. Those cheeks reddened further.

But also nervous? Oh, god, more nervous than she could ever remember being.

A brief glance back to Futaba, then back to the hole. Gulp. Makoto closed her eyes and stepped forward.

She didn't fall all the way in. Her eyes snapped open to gaze around the entrance of Mementos. There was immense pressure - no, immense  _ tightness _ , her body being squeezed down on at the hips. But she wasn’t moving. "I-I'm stuck?"

Her legs had slid in. Her fat ass had managed to compress and roll just enough for (most of) it to fit past that hole. But her hips? Those wide hips were just…  _ too _ wide, just couldn't  _ quite _ fit into that narrow opening, and Makoto was left… awkwardly hanging with the porthole squishing down on her body. 

If Futaba had been delighted at seeing her friend take the plunge, then she was  _ ecstatic _ with the following result. Crouching down, she pressed a pudgy finger against the top of Makoto's ass - at the excess fat that had bunched up over the porthole and was stuck lingering outside. "Wow. I don't think you even need my help powerleveling your pudge! Your fat, plump ass has got you super stuck."

That poke and those teasing words made Makoto whine a tiny bit. A little bit of squirming, trying to brace her arms against the floor and push up, but... it did little, besides jiggling the fatty flesh that bulged past the undersized hole. Makoto was truly stuck even if she wanted to free herself.

There was some amount of thrill in that.

Futaba knelt down, wrapping her arms around Makoto from behind, cuddling her at waist level, her arms practically resting on the floor in order to do so. She didn't seem at all disappointed, even if this seemed to make their impending fun a thorny, hard-to-reach issue….

Or maybe not. "It is not f- _ fat- _ ?" The protest on Makoto’s lips slid loose and her pitch grew higher at a sudden touch against her legs. It was unexpected and terrifying, the exact same feeling as brushing a foot against  _ something _ unseen at the beach. She leaned back a little, pressing her back against Futaba and biting down on her lip. "O-Oh gosh." Her legs swung, just a little bit.

_ Something _ was sliding up the inside of Makoto's leg. It felt wet, slightly warm and a strange kind of... fleshy?

The tentacle entwined, curling, wrapping, squeezing. It coiled lovingly around Makoto's leg, throbbing against it - there was a definite sensation of something  _ full _ inside that tentacle, some manner of payload it wanted to deliver. Well, just that tentacle, or perhaps many more...? They weren't wasting time. It was as if the floor rose to meet Makoto's dangling legs, swallowing them up, surrounding her from below.

Were someone to make a cross-section of the situation, they'd see Necronomicon, upside-down, pressed tight to the floor from below, engulfing Makoto's lower body in thick, purple, bulging appendages. Appendages which slipped up along her legs, writhed against her ass and squirmed against her crotch like fat, desperate worms, rubbing away. Whatever they secreted from their pores, it seemed to be pretty good at dissolving clothing!

"Mm... disagree. You've got a fat, heavy ass and if you weren't stuck right now, guess where my face would be!" Futaba wasn't holding anything back, her plump body pressed up against her partner's back. "But you had to go and spoil all our fun by getting stuck." It had hardly been spoiled at all!

It was difficult for Makoto to miss all the stares such a fat, heavy ass drew on the daily - not the least of which had been from Futaba gazing at the tight backside of her thief outfit, or the flashes of her tights from her undersized school uniform skirt. Most of Makoto's body was rather trim and fit - a little toned, even! Apparently, what weight she  _ did _ accrue had chosen to pile up in her lower half.

But Makoto wasn’t thinking about that right now, because she was too preoccupied with tentacles. Tentacles! Tentacles that Makoto could feel were bulging with  _ something _ \- coiled around thick thighs, and she felt her legs, and then her crotch, engulfed. Secreted wetness against her clothes, a strange feeling of a breeze on her legs - and Makoto could feel the lower half of her clothes melting away. 

...and that fat derriere seemingly grew just a bit  _ fatter _ with no constricting clothing keeping it packed away. A tiny bit more ass spilled out past the hole Makoto was stuck in, and between those uncovered cheeks, a woefully-undersized pair of striped panties rode  _ high _ up her ass, waistband squishing down against her hips. Tendrils rubbed between her legs, against her fattening mons bulging out her panties, and Makoto couldn't bite back the quiet moan.

There it was - the first little moan. It thrilled Futaba to hear, reminding herself of the first moments she'd treated her lithe body to a tentacle bath, squirming and squeaking. She un-digitized the glove portion of her bodysuit, leaving her bare fingers to slide up and down Makoto's hips, attempting to soothe her, feeling out the waistband that sunk against, dug into, her generous flesh. "Oh? ...Oh, I see. You didn't want to face the shame of buying bigger underwear at the store. It's okay; they can't melt clothing that isn't our special outfits, so this is safe!"

"N-Not quite," Makoto sputtered out, voice breathy and hitching at the sensation of bunching tentacles against her legs and Futaba’s soft fingers against her hips. "I just...." Pant, pant. "It's hard to find any that fit better." By now, the aloof masquerade had been shattered completely - Makoto’s voice was warbling and trembling with nervousness… and incredible anticipation and arousal.

One progressive, attentive tendril worked hard to squish against Makoto's buttocks, squirming and slipping about, fighting to, to- Ah! It managed it! It hooked right under the bunched-up seat of those panties and pulled it out, causing the front end to likewise sink in against her puffy mound. Those panties were so incredibly  _ tight _ that it looked like those tentacles would only be able to take care of one side at a time. Which side that was…. Well. The fact that various fat-headed tendrils were squirming, flip-flopping over the puckered skin of Makoto's exposed anus, all desperately squeezing between her heavy, wobbling asscheeks in order to be the first inside? That was probably a giveaway.

Futaba slipped her hand into one of Makoto's, giving it a squeeze. Her other began to make little touches atop the girl's belly, which…. Well. It wasn't going to remain trim and firm for long. "Riiight. I don't think there's a pair in the world that are going to fit you when we're done here!”

They did feel  _ very _ wet and slimy. There was seemingly no friction whatsoever! "Sooo. Since this is how it turned out, I'm going to let them do whatever, okay? Where are they attacking right now, Queen? Send me the data!"

A little yelp from Makoto as her panties were forcibly tugged, riding up between her cunt, grinding against her crotch. And then those slick tendrils between her cheeks, slime coating her rear as they rode up her ass and glided against her skin. Fuck, there were just so  _ many _ conflicting little touches, each push and press and squirm of that army of tendrils igniting a fire of sensations inside her. She could feel each and every one - the different levels of pressure they applied as they pushed against her skin, the ones rubbing deeper against her slowly-dilating backdoor. Hellish, slick, wet overstimulation that felt so  _ good _ .

Futaba's words gave Makoto a little pause, and she glanced back over her shoulder as well as she could manage with her body so damn stuck. A hint of nervousness: "'Do whatever?' I-Is it safe to let them just-?!" And then cutting herself off, eyes jolting wide, as there was sudden slick wetness and another layer of  _ pressure _ between her cheeks, somewhere Makoto had never even  _ considered _ using for such  _ indecency! _

She involuntarily rolled her hips as little as her body could, stuck as it was. An aroused, quivering exhale, trying to catch her breath. "They're... touching my... b-b...."

Proper little Makoto was too embarrassed to say it. She flashed a shaky smile at Futaba.

“I don't really know,” Futaba fired back, worryingly-cheerful. “I've never let them do whatever they wanted and I can't be bothered to rein them in. Let's find out!"

She was excited, interested, and leaning heavily against her friend's back, almost rubbing herself against it - this allowed her to rest her chin on Makoto's shoulder, pressing cheek to pudgy cheek. Now, Futaba was an anal freak. A complete anal freak - her first time had been anal, it's what she adored with her tentacles and it's what her secret little sexual stats all revolved around. Those tentacles were  _ designed _ for anal. Frictionless, with an intensifying secretion that would gradually build up Makoto's pleasure to the point where any sort of external or anal stimulation could be compared with direct clitoral stimulation! How quick she gets there was entirely up to her own fantasies; she might be able to resist it at first, but….

Makoto, on top of everything else, was feeling a twinge of mounting worry as Futaba haphazardly dismissed the safety of the tentacles on the verge of utterly stuffing her butt, but, well, Makoto wasn't exactly in the best spot to bow out now. She could only chuckle nervously, eyes turned to look towards Futaba as their bodies pressed together. "Wait, you've never-?

"Guh-!". Oh, it looks like one of the tentacles had one. A cock-like tip squirmed,  _ writhed _ against Makoto's backdoor, discharging some manner of fluid into her ass. So much mounting pressure against her ass, and the utterly bizarre sensation of...  _ something _ pouring into her, slickening that tight tunnel. Makoto shook her legs, and her ass cheeks jiggled a bit as she adjusted herself. She straightened her body, doing her best to relax herself, to loosen herself as that tendril pushed and squirmed as it tried to slip right into a rim that seemed like it should be  _ far _ too tight for it. The size difference didn't seem to dissuade that tentacle in the least, though - oh,  _ god _ , Makoto was definitely going to have to stretch.

"So…,” Futaba said. “Start counting backwards from ten, okay? Slowly. This is how I prepare, so use your Oracle's advice!"

Makoto gulped, and gave a little nod. "T-Ten." Breath. "Nine." Breath, breath. "E-Eight...."

Eight was as far as Makoto got. Before she could even utter the next number, something  _ writhed _ . It slathered its ejaculate over her anus, spread it  _ wide _ , and jammed itself inside, breaking the threshold! Her voice cracked, and her hand squeezed down on Futaba's. But that tendril didn't slide in too far. No - it began to swell, throbbing, pulsing, warping and increasing in size as fluid flowed into it, half of which discharged wetly into Makoto's bowels in a constant flowing gush, while the rest seemed to help the tendril form some sort of… plug. Liquid bulged out that tentacle, spreading the already-stretched inner walls of Makoto's ass, and leaving her backside thoroughly  _ plugged _ and airtight. Oh, she felt…  _ full _ . So very, achingly  _ full _ .

Futaba spoke over Makoto’s quiet moans… and the subtle gurling of her stomach. "So the first thing they do is imprint your asshole while leaking inside you. That cum slurry you're feeling right now? That's there to change your body on the inside, to make it so much easier for them to do more and more to you." Makoto’s eyes widened as she felt an ominous rumbling, deep in her tummy. "As that fluid goes through your guts, it's going to expand your tummy. Bet you anything your panties are going to break."

Already, Makoto felt an idle, dull pressure in her belly. "E-Expand my..." Makoto parroted dimly, looking down at herself.

As that warm, fluid mess kept expelling into her, the lack of leakage quickly became apparent - she was too stretched and  _ stuffed _ for anything to seep past that plug, and instead she was left with the sensation of that cummy mess pooling inside her bowels - and then deeper, starting to push into her guts. Between inarticulate, babbled syllables and bit-back moans, Makoto found her voice again - "Ch-Change my body... h-how, exactly?"

That goop just kept coming. Gravity had something to say about the progress, but as it piled up inside Makoto's intestines, the sheer volume of it allowed it to go further,  _ further _ . It felt entirely clogged near the plug, but deeper... something flowed. The weight of all the cum in her guts quickly began to show, stretching out the front of her suit as her tummy expanded to make room for all the added presence. That suit was going to take some punishment! How long could that area of it hold out before it tore open, revealing her rounding tummy?

Futaba shuffled around on her knees to in front of Makoto, showing off her chubby belly and even cupping it with her free hand, giving it a wobble through the figure-hugging suit. "You're going to look just like your favourite Oracle, duh. Maybe a little bigger... but it goes down quickly and normalizes! Let me know when it starts filling your tummy from below, okay?"

Cognition had such a funny way of changing things - Makoto didn’t know it, but how big her stomach would get was mostly up to how big she  _ thought _ it could expand... then  _ just a little _ past that point.

The volume of thick, messy cum started pushing further up through Makoto, and she was already beginning to feel bloated before it started actually showing. Her guts stretched, and there was an audible gurgling in her midsection. Fuck, how much was it going to dump into her?

She could only huff and moan at the bizarre sensations of getting so  _ filled _ , looking down at herself, trembling a tiny bit. Her insides felt so…  _ stuffed. _ Wet, liquid-y, heavy and sloshing. It wasn't much longer before her tummy started quivering, and....

"Oh. Oh wow." The faintest hint of a paunch started appearing beneath the tightness of Makoto's outfit. Every inch of her guts were filled, and with nowhere else for it to go, Makoto had to start expanding. It was faint. Barely noticeable unless you were really looking for it.

But it was getting bigger.

And through it all, Futaba was  _ very _ excited. She was getting to see someone else enjoy what she had done so before - and it was really only the first step of a long process. First came the preparation and expanding, then - Ooh. So much more. But she wanted to focus on the  _ here _ and  _ now _ . Like the gurgling, the rumbling...! The creak of Makoto's bodysuit as it fought against the incoming tide!

"Nnngh... I... feel  _ really _ full, Futaba...." Weren’t they always supposed to be using codenames in here? Poor Makoto was too  _ full _ to think of that right now.

The subtle bloat was filling, stretching, Makoto’s tummy starting to push past the rim of the hole she was stuck in. She let her free hand rest on her middle, gulping as she watched her hand slowly lift further away as she ballooned outwards. Those panties were holding up well, starting to sink further into Makoto's flesh. Other parts of her were swelling up as well, including her… her….

Makoto blinked. There was another sensation - her ass  _ squishing _ further into the hole it was crammed into, more fat flesh starting to roll across the rim and bulge outwards. She craned her head back upwards to look at Futaba. "Futaba, is my b-butt-?"

_ Snap! _

And then her eyes went back to staring down at herself, as she watched that poor leather girdle stretch, strain against that oncoming tide, and then finally  _ snap _ in twain - and her bloated tummy surging forward to fill the space it had occupied. The rest of her top didn't last much longer - that black bodysuit split down the middle, leaving her belly exposed to the air as she cried out. With the bottom half already dissolved by that tentacle’s  _ gunk _ , Makoto was finding herself worryingly-close to losing her clothes entirely - naught but just enough of that suit to cover the modesty of her chest, a few pathetic scraps of leather sticking to her arms and back, the metal mask across her eyes, a nearly-snapped pair of panties, and that long, loose scarf reaching down from her neck to draping onto the floor. 

Already did she look well into the depths of a full-term pregnancy, her stretched tummy high and taut at the mass of cum leaving not an inch unfilled. She rested a hand on it again, feeling the liquid stirring inside it, hearing the loud complaints as it  _ gurgled _ and swelled.

Futaba leaned in, oh-so-close to squirming, moaning Makoto. That hand went from rubbing across that burgeoning belly to taking a nice, big handful of its pale, fattening flesh. "Ooh. You look amazing! But! It's going to fill up entirely soon, and start going higher.... You'll let me drink it from your mouth, right?"

Makoto blinked. "Wait, from my m-mouth?" Her navel popped outward, and she cried out.

Pump, pump, pump....

Futaba grinned. "Well, I can't have any fun when you've got your  _ piggy butt _ cramming the ho-" 

Pump, pump,  _ snap! _

The waistband of Makoto's underwear gave way, causing it to flop outwards uselessly, allowing her bottom to jiggle freely from any and all movement. Corset, suit, underwear... she'd have to get used to feeling those rip - and  _ more _ in the future, when her body was all properly warmed up! Futaba’s hands went lower, lifting Makoto’s belly - fuck, it was  _ heavy! _ \- from below. "Ooh….  _ Mmm _ . Like I was saying. I want to get  _ big _ too. Oh - here we go!" She saw her cue - Makoto's expression!

Makoto's expression was  _ already _ amazing. Constant disbelief, a mixture of surprise and anxiety. But when tentacle cum started travelling up your throat from below, well. That's when it  _ really _ got intense! Throat suddenly widening, thickening, bulging with cum, Makoto’s eyes widening to dinner plates in shock, her lips curling backwards and her cheeks bloating out as it surged into her mouth! And just as it started to flow out, Futaba was there to seal her lips against Makoto's, drinking the thick goop that had bloated her out, dumping it directly in her own stomach as it pumped from one end to the other. Futaba's hands held the back of her friend's head to keep things tight, keeping their mouths jammed together and barely allowing any of the fuckslime to escape their lips (it was... purple? Purple!) and swallowing, swallowing….

Her body had been through the routine before. She was ready for the changes, primed for them. It didn't take much of the slime to cause her own outfit to rip, to tear open and her fat belly to  _ flump _ out, navel inverted, squishing against Makoto's same-size tummy. As soon as that happened, Futaba broke the kiss, licking her lips as she knelt backwards, showing off her widened hips, bloated tummy, chunky thighs. The flow of tenta-cum had stopped too, though the tendrils hadn't left Makoto's ass just yet.

"Want to stay-" Futaba quickly swallowed the urge to burp - "...urp, here overnight?"

**Author's Note:**

> if you enjoyed this, please, please, please leave a comment! i read every single one and they super brighten up my day every single time.
> 
> if you _really_ enjoyed this and want more like it, i'm always looking for new writing partners and people to chat with about smutty stuff! come say hi on my twitter - [@verylargetv](https://twitter.com/verylargetv) \- or add me on discord - @ averylargetelevision#6506
> 
> and as mentioned above, the other author of this story can be found under the username Hackerchan on F-List!


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